August 11th, 2011
12:44 PM ET
A step toward a new possible treatment for leukemia, one that uses patients’ own immune cells to target and destroy cancer is getting a lot of media attention.
It should be noted, however, that the therapy, however promising, has been tested in only three patients, who had varying side effects such as fevers as high as 104 degrees, heart dysfunction and breathlessness. Most of the side effects resolved themselves within a matter of weeks.
A year after the therapy, two of the patients had complete remission of leukemia and one had a partial response to the therapy (meaning the patient still has cancer, but a less severe case). All three were suffering from chronic lymphocytic leukemia, one of the most common types of the disease that affects blood and bone marrow.
Published Wednesday in both the New England Journal of Medicine and Science Translational Medicine, researchers reported that they had been able to engineer the patients’ own white blood cells into “serial killers” to destroy the cancer cells.
The research team from the University of Pennsylvania's Abramson Cancer Center and Perelman School of Medicine extracted white blood cells from the patients and genetically reprogrammed them to attack tumor cells.
They programmed the T cells, which are a blood cell type that protects the body from infection, to bind to a protein that is expressed in chronic lymphocytic leukemia tumor cells. Doctors infused the modified T cells back into the patients’ bodies.
"Within three weeks, the tumors had been blown away, in a way that was much more violent than we ever expected," said Dr. Carl June, senior author of the study, in a university press release. "It worked much better than we thought it would."
One of the trial participants wrote in a first-person essay, "I'm healthy and still in remission. I know that this may not be a permanent condition, but I decided months ago to declare victory and assume that I had won."
The study could have implications for leukemia, which develops in about 43,000 people every year, according to the Leukemia & Lymphoma Society. Treatment for leukemia is difficult because bone marrow transplants are the best bet for survival. But transplants come with high risk of complications and difficulty matching donors.
Two weeks after the T-cell transfusion, nothing seemed to change. But then, the man started having high fever, chills and nausea. Tests showed a dramatic increase in T cells in his blood and massive cancer cell death. This was life-threatening, because his body became clogged with so many dead cells, according to CNN affiliate, Philly.com.
A month after the transfusion, his blood and bone marrow showed no evidence of leukemia.
For leukemia patients, this cell trial is on hold and not enrolling additional patients at this time, according to the University of Pennsylvania's website. The trial will reopen in the next one or two months, but very few patients will be able to be treated.
Despite promising results, an accompanying editorial in NEJM urged caution because of side effects such as the depletion of B-cells, which are a type of white blood cells that produce antibodies to fight off infections.
“Only with the more widespread clinical use,” wrote the editorialists, Dr. Walter Urba and Dr. Dan L. Longo, “will we learn whether the results reported… reflect an authentic advance toward a clinically applicable and effective therapy or yet another promising lead that runs into a barrier that cannot be easily overcome.”
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